Re: pgsql: Document XLOG_INCLUDE_XID a little better

On Sun, Oct 3, 2021 at 5:05 PM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
>
> On Sat, Oct 2, 2021 at 8:10 PM Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> wrote:
> >
> > On 2021-Oct-02, Dilip Kumar wrote:
> >
> > > I have written two patches, Approach1 is as you described using a
> > > static boolean and Approach2 as a local variable to XLogAssembleRecord
> > > as described by Amit, attached both of them for your reference.
> > > IMHO, either of these approaches looks cleaner.
> >
> > Thanks! I haven't read these patches carefully, but I think the
> > variable is about assigning the *subxid*, not the topxid. Amit can
> > confirm ...
>
> IIRC, this variable is for logging the top xid in the first WAL by
> each subtransaction. So that during logical decoding, while creating
> the ReorderBufferTxn for the subtransaction we can associate it to the
> top transaction without seeing the commit WAL.
>

This is correct.

--
With Regards,
Amit Kapila.